Electric incandescent lamp



p 1964 K. SASSMANNSHAUSEN 3,149,259

ELECTRIC INCANDESCENT LAMP- Filed May 20, 1960 D INVENTOR Knut SaBmannshausen ATTORNEY United States Patent 3,149,259 ELECTRIC INCANDESCENT LANE Knut Sassmannshansen, Idar-Oherstein 3, Rothenbach, Germany Fiied May 20, 196i), Ser. No. 30,600 Claims priority, application Germany Jane 2, 1959 3 Claims. (Cl. 313-275) The present invention relates to an electric incandescent lamp in which the mount is spaced at predetermined distance from the lamp envelope, more particularly to a miniature incandescent lamp, and preferably to a lamp including a lens shaped portion in the dome of the envelope, and to a reflector lighting fixture containing such lamp.

Lamps of this type require a very accurate location of the filament in the lamp envelope to ensure proper positioning of the filament with reference to the reflector and thus the desired distribution of radiation. On sealing the lamp mount in the envelope provision should be made to prevent displacement of the mount and, thereby, of the filament due to the softening of the glass. Furthermore, the filament must be safeguarded against displacements resulting from vibrational shocks of the finished lamp and occurring, for instance, with vehicle headlamps. Often, the permissible maximum tolerances amount only to 0.1 mm. or less.

Hitherto, the said requirements have been met by extending one or both lead-in wires beyond the filament mounting place and by either engaging one of the extended lead-in wires in a recess of the dome of the envelope or, in case of lamps with a lens portion, by guiding both extended lead-in wires to the periphery of the lens. A disadvantage of the said mount supports consists in that the extended lead-in wires create shades and that the dimension of the lens is limited. For the end portions of the lead-in wires bearing upon the periphery of the lens must be spaced from each other a distance corresponding to the lens diameter respectively, and said distance should be small enough to enable insertion of the lamp mount through the comparatively narrow envelope neck which is dimensioned in accordance with customary commercial sizes of base and socket. Besides, if one of the lead-in Wires is supported by the dome of the envelope the risk is run that said comparatively long lead-in wire sags.

The said disadvantages are overcome by the present invention which permits a shadeless radiation and, with lamps comprising a lens portion, an enlargement of the lens thereby providing a remarkable improved lighting. With an electric incandescent lamp, more particularly a miniature incandescent lamp and preferably a lamp comprising a lens portion in which the mount is spaced a predetermined distance from the lamp envelope, the invention consists in providing the mount support adjacent the filament between filament and mount seal. Inwardly directed projections of the envelope serve as stop means for the supporting members. The inside width of the envelope between the inwardly directed projections is smaller than the inside width near the periphery of the lens which will be termed internal lens diameter throughout the description. With lamps comprising an envelope with an end portion narrowing to a neck opposite to the dome shaped portion the inside width thereof is smaller at the inwardly directed projections than at the neck of the envelope. With lamps comprising a lens portion the internal lens diameter is larger than the inside width of the envelope neck.

The invention is described by way of example in the accompanying drawings wherein some of the figures are not draw to scale but are enlarged instead. All features of the examples are alternately exchangeable and, instead 3,149,259 Patented Sept. 15,, 1964 of with miniature lamps, also applicable with other types of incandescent lamps.

FIG. 1 shows an incandescent lamp in longitudinal section prior to sealing the mount.

FIG. 2 shows an incandescent lamp with a lens portion in longitudinal section with the exhaust tube sealed there- FIG. 3 shows an incandescent lamp with a lens portion in longitudinal section prior to sealing the exhaust tube foot.

FIG. 4 is a cross-section of the lamp as shown in FIG. 3, taken along the line 44 of FIG. 3 and viewed in the direction of the arrows.

FIG. 5 shows a based incandescent lamp with a lens portion mounted in a reflector in side elevation, partly in section.

FIG. 6 shows diagrammatically a based incandescent lamp with a lens portion mounted in a reflector in side elevation, partly in section.

The lamp envelope according to FIG. 1 comprises a ball-shaped portion 1, a conical portion 3 and a cylindrical portion 6. An annular constriction or indentation is located between ball-shaped portion 1 and conical portion 3, to form intermediate the constriction and conical portion 3 an annular shoulder 2. The filament S is carried by lead-in wires 4 and 5 which are kept in spaced relationship to each other by bead 8 and extend beyond the mounting places of the filament to form outwardly bent end portions it and 11 abutting the annular shoulder 2, whereby the mount is spaced at predetermined distance from the envelope. The ball-shaped portion 1 of the envelope can comprise a reflecting area 12. On lamp manufacture the insertion of the mount with outwardly bent end portions of the lead-in wires provides no (llfilCllltiCS since the most narrow portion of the envelope is constituted by the constriction.

Referring to FIG. 2, 2t desi nates a planoconvex lens to which is joined a frustoconical envelope portion 21 extending in tapered form to the narrowest portion of the envelope and then merging with annular shoulder 22. Adjacent the latter are a cylindrical envelope portion 23 and the neck 24. The exhaust tube 25 is sealed to neck 24 and lead-in wires 26 and 27 are likewise sealed in this place. The rod-shaped head 28 keeping lead-in wires 26 and 27 spaced from each other serves at the same time for supporting the mount by bearing against annular shoulder 22. The width of bead 28 is smaller than the internal diameter of neck 24 and the latter is smaller than the internal lens diameter.

FIGS. 3 and 4 disclose an incandescent lamp wherein the concavoconvex lens 3%) passes into a cylindrical bulb portion 31. U-shaped indentations are provided on opposite sides comprising a U-bend or inwardly extending indentation 32 and U-legs 33 and 34. All U-legs are arthereof has a conductor element secured to the bottom ranged in parallel to the axis and the U-bends are evenly spaced from the dome of the envelope. A supporting wire 41 sealed in the glass bead 39 is designed for support, this supporting wire on insertion of the mount being guided in grooves formed by two mating U-legs 33, 34 each and bearing against inner shoulder faces 32a of the U-bends 32. Provided, supporting wire 41 consists of metal it may be welded alternately to one of the lead-in wires 35 or 36. The outer end portions of lead-in wires 35, 36 project outwardly intermediate the bulb rim 37 and exhaust tube foot 38. On sealing the open sides of the U-shaped indentations are closed. For this purpose it is advantageous to provide the U-legs at the rim of the envelope 37 flatly shaped and smaller than at the U- bends. The coiled filament 49 is arranged in V-shape.

Alternately, the opposed indentations can be designed so as to merge into guide tracks which are adjacent the bends 32 serving as stop means, these guide tracks not being directed to the rim of the envelope 37 in parallel to the axis but extending helically around the cylindrical envelope portion 31 towards the rim of the envelope 37. When inserting the mount in the envelope, said mount executes a twisted movement with regard to the envelope till supporting wire 41 abuts the stop.

FIG. shows a paraboloid reflector 65 wherein a lamp is mounted. This lamp comprises a biconvex lens 50 having an outer surface designed as hyperboloid. The internal lens diameter should amount to at least 7 mm. and is 8 mm. in the present case. The distance between the tip of the inside lens surface and the lens plane designated by a dotted line shall be in the range of from 18% to 30% of the lens diameter and amounts in the present case to 1.44 mm. Adjacent lens 50 there is a bulb portion 51 tapered in frustoconical manner and merging into constriction 52. Adjacent the constriction 52 and annular shoulder 53 extends an enlarged portion 54 with neck 55. The diameter of constriction 52 is smaller than that of neck 55 and the neck diameter is smaller than the internal lens diameter. The lead-in wires 56 and 57 are kept in spaced relationship to each other by bead 59 and carry the filament 60. The distance of filament 60 from the lens plane measured in millimetres can be in the range of between 80% and 150% of the magnitude of the ratio lens diameter to lens thickness and, in the present case, amounts to 2.08 mm. The end portions 62, 63 of lead-in wires 56 and 57 are bent outwardly and bear against annular shoulder 53. The prefocus base 58 is provided with an adjustment ring 61. Locating bosses 64 are mounted in customary manner on the adjustment ring 61 and corresponding stop means are provided on the Searchlight lantern. On basing the lamp, adjustment is effected in such a manner that the plane contacting the locating bosses is spaced at predetermined distance from the filament. Said distance is so chosen as to arrange for the filament to be located in the reflector focus. When using a paraboloid reflector of conventional size, as in the present case, said distance amounts to 026310.006 inch, measured from the top of the unlighted filament to the top of the locating bosses.

As shown in all embodiments, the mount bears against the envelope wall near the mounting places between filament and lead-in wires whereby proper positioning of the filament in the lamp envelope on sealing of the mount as well as during vibrational shocks of the finished lamp is ensured most effectively.

Another advantage of supporting the mount in the manner described above is that the dimension of the lens can be chosen independent of the width of the supporting memhers and the diameter of the envelope neck. By enlargement of the lens it is also possible to increase the distance between filament and lens so that the blackening of the lens by the filament is decreased.

FIG. 6 shows a paraboloid reflector 71 wherein a lamp 72 with a lens portion is mounted in such a way as to arrange for the filament 75 to be positioned in the reflector focus at the point of intersection of line AB and optical axis CD. The envelope wall 76 of the dome is shaped as biconvex lens having an outer surface '73 designed as hyperboloid. The internal lens diameter should amount to at least 7 mm. and is 8 mm. in the present case. The distance a between the inside lens surface 74 and the lens plane designated by line KL in the optical axis CD shall be in the range of from 18% to 30% of the lens diameter and amounts in the present case to 1.44 mm. The distance of filament 75 from the lens plane measured in millimeters can be in the range of between 80% and 150% of the magnitude of the ratio lens diameter to lens thickness and, in the present case, amounts to 2.08 mm. The distance between the filament top next to the dome of the envelope and the rim of the base 77 is in the range d of from 55% to 100% of the lens diameter and is designed to be at least 4 mm. In the present case it amounts to 5.52 mm. Sketched base 77 can be designed as screw base, as prefocus base as represented in FIG. 5, or any other type of base.

The lighting fixture outlined in FIG. 6 with its reflector 71 preferably mounted in rigid connection but also designed to be adjustable in the optical axis emits longrange and short-range light beams at the same time. Light from filament directly striking the reflector 71 creates the sharply bounded long-range light beams. The total radiation of filament 75 not striking the refiector 71 which, without lens, would form the light beam marked by a dotted line leading from the filament to points E and F, is engaged by the lens and formed to a moderately concentrated light beam providing an excellent shortrange light. The radiation emerging from the lens illuminates an area of 7,500 to 15,000 cm. on a screen arranged vertically to the optical axis at a distance of 1 m. This is equivalent to a disk having a diameter of approximately 1 m. or more. The said broad short-range light beam is rendered possible by the enlargement of the lens.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An electric incandescent lamp comprising, in combination, a glass bulb having a rear socket end and a front end and being formed intermediate said front and rear ends and distant from said rear socket end with a constriction forming an inner shoulder face extending transverse to the longitudinal axis of said bulb and facing toward said socket end, said bulb having between said socket end and said constriction a substantially cylindrical configuration; a filament located in said bulb between said constriction and said front end of said bulb and spaced a short distance from said shoulder face; a pair of lead-in supporting wires respectively fixed in the region of one end portion thereof to opposite ends of said filament and the other end portions thereof passing fluid tightly sealed through said socket end of said bulb at a distance from said shoulder fac which is greater than said short dis-' tance; abutment means fixed to said lead-in wires and abutting against said face of said constriction for stably holding said filament at a fixed distance from said front end of said bulb even during softening of the glass of the bulb at said socket end during sealing of said socket end 7 at elevated temperature; and a pair of oppositely arranged and axially extending guide grooves formed in said cylindrical portion of said bulb for guiding said abutment means during insertion thereof in said bulb and for fixing the angular position thereof with respect to the axis of the bulb.

2. An electric incandescent lamp comprising, in comlbination a glass bulb having a rear socket end and a front end and being formed intermediate said front and rear ends and distant from said rear socket end with an annular constriction forming a transverse inner shoulder face substantially normal to the axis of said bulb and directed toward said socket end; a filament located in said bulb between said annular constriction and said front end of said bulb and spaced a short distance from said shoulder face; a pair of lead-in supporting wires respectively fixed in the region of one end portion thereof to opposite ends 'of said filament and the other end portions thereof passing fluid tightly sealed through said socket end of said bulb at a distance from said shoulder face which is greater than said short distance; and abutment means abutting against said face of said annular constriction and being constituted by end portions of said lead-in wires extending transverse to the axis of said bulb and respectively in opposite directions beyond the points to which said filament is attached to said lead-in wires for stably holding said filament at a fixed distance from said front end of said bulb even during softening of the glass of the bulb at said socket end during sealing of said socket end at elevated temperature.

3. An electric incandescent lamp comprising, in combination, a glass bulb having a rear socket end and a front end and being formed intermediate said front and rear ends and distance from said rear socket end with an annular constriction forming an inner shoulder face extending transverse to the longitudinal axis of said bulb and facing toward said socket end; a filament located in said bulb between said annular constriction and said front end of said bulb and spaced a short distance from said shoulder face; a pair of lead-in supporting wires respectively fixed in the region of one end portion thereof to opposite ends of said filament and the other end portions thereof passing fluid tightly sealed through said socket end of said bulb at a distance from said shoulder face which is greater than said short distance; a glass bead fixed to said lead-in wires in the region of said one end thereof; and abutment means in the form of a Wire sealed intermediate the ends thereof to said glass bead and extending transversely to the axis of said bulb and abutting with opposite ends thereof against said face of said annular constriction for stably holding said filament at a fixed distance from said front end of said bulb even during softening of the glass of the bulb at said socket end during sealing of said socket end at elevated temperature.

References Cited in the file of this patent UNITED STATES PATENTS 563,321 Scribner July 7, 1896 692,294 Jaeger Feb. 4, 1902 1,306,259 Keyes June 10, 1919 1,594,635 Skogland Aug. 3, 1926 1,657,410 Porter Jan. 24, 1928 1,983,362 Geiger et a1 Dec. 4, 1934 2,142,104 Birdseye Jan. 3, 1939 FOREIGN PATENTS 192,243 Austria Oct. 10, 1957 

1. AN ELECTRIC INCANDESCENT LAMP COMPRISING, IN COMBINATION, A GLASS BULB HAVING A REAR SOCKET END AND A FRONT END AND BEING FORMED INTERMEDIATE SAID FRONT AND REAR ENDS AND DISTANT FROM SAID REAR SOCKET END WITH A CONSTRICTION FORMING AN INNER SHOULDER FACE EXTENDING TRANSVERSE TO THE LONGITUDINAL AXIS OF SAID BULB AND FACING TOWARD SAID SOCKET END, SAID BULB HAVING BETWEEN SAID SOCKET END AND SAID CONSTRICTION A SUBSTANTIALLY CYLINDRICAL CONFIGURATION; A FILAMENT LOCATED IN SAID BULB BETWEEN SAID CONSTRICTION AND SAID FRONT END OF SAID BULB AND SPACED A SHORT DISTANCE FROM SAID SHOULDER FACE; A PAIR OF LEAD-IN SUPPORTING WIRES RESPECTIVELY FIXED IN THE REGION OF ONE END PORTION THEREOF TO OPPOSITE ENDS OF SAID FILAMENT AND THE OTHER END PORTIONS THEREOF PASSING FLUID TIGHTLY SEALED THROUGH SAID SOCKET END OF SAID BULB AT A DISTANCE FROM SAID SHOULDER FACE WHICH IS GREATER THAN SAID SHORT DISTANCE; ABUTMENT MEANS FIXED TO SAID LEAD-IN WIRES AND ABUTTING AGAINST SAID FACE OF SAID CONSTRICTION FOR STABLY HOLDING SAID FILAMENT AT A FIXED DISTANCE FROM SAID FRONT END OF SAID BULB EVEN DURING SOFTENING OF THE GLASS OF THE BULB AT SAID SOCKET END DURING SEALING OF SAID SOCKET END AT ELEVATED TEMPERATURE; AND A PAIR OF OPPOSITELY ARRANGED AND AXIALLY EXTENDING GUIDE GROOVES FORMED IN SAID CYLINDRICAL PORTION OF SAID BULB FOR GUIDING SAID ABUTMENT MEANS DURING INSERTION THEREOF IN SAID BULB AND FOR FIXING THE ANGULAR POSITION THEREOF WITH RESPECT TO THE AXIS OF THE BULB. 